Electronic devices, such as integrated circuits, are manufactured by, for example, forming wire traces and other circuit patterns on thin slices of chips cut from a silicon or other wafer. FIG. 10 illustrates an example method for manufacturing electronic devices. Referring to FIG. 10(A), rectangular chips 110, each having a predetermined size, are segmented on a front surface of a wafer 100. Additionally, as illustrated in FIG. 10(B), a pattern forming apparatus not illustrated is employed to cause a front surface of each of the chips 110 segmented into the predetermined size to be subjected to a patterning. This forms a circuit pattern 111, such as a wire trace pattern, on the front surface of each of the chips 110 of the wafer 100.
In addition, referring to FIG. 10(c), a dicing apparatus not illustrated is employed to cut the wafer 100 into the chips 110, thereby obtaining the chips 110 with patterns formed thereon. This results in the circuit pattern 111 being formed on the front surface of each of the chips 110 and each chip 110 divided by the cutting serving as an electronic device 112. Conventional examples are described in Japanese Laid-open Patent Publication No. 10-56349, Japanese Laid-open Patent Publication No. 04-87408, and Japanese Laid-open Patent Publication No. 11-288881.
The method for manufacturing the electronic device 112, however, involves burr formed on a cut surface 110A of the chip 110 during the step of cutting of the chip 110 on which the pattern is formed from the wafer 100. FIG. 11 illustrates an example external configuration of the electronic device 112 manufactured through the manufacturing method illustrated in FIGS. 10(A) to 10(C). Specifically, as illustrated in FIG. 11, the burr X is formed on the cut surface 110A of the chip 110 during the step of cutting of the chip 110 on which the pattern is formed from the wafer 100. The burr X on the chip 110 formed during the step of cutting may make a foreign object when, for example, the chip 110 is encapsulated in a synthetic resin or other package. In this case, the burr X on the chip 110 sticks to the circuit pattern 111 on the front surface of the chip 110, thus causing the circuit to be short-circuited, which may make the electronic device 112 a reject.
Understandably, the burr X formed on the cut surface 110A of the chip 110 may be removed. Individually polishing the chip 110 on which the pattern is formed may be, for example, one possible way to remove the burr X from the chip 110. It is, however, important to pay attention to the chip 110 after pattern formation so as not to damage the circuit pattern 111 formed on the front surface of the chip 110 during removal of the burr X. This requires a large workload during the removal of the burr X. Specifically, removing the burr X on the chips 110 altogether without damaging the circuit patterns 111 is a difficult task to perform.
Accordingly, it is an object in one aspect of an embodiment of the invention is to provide an electronic device manufacturing method, an electronic device, and a chip assembly that permit burr to be removed from a plurality of chips altogether.
According to an aspect of an embodiment, an electronic device manufacturing method includes: cutting a wafer to obtain chips on which patterns are yet to be formed; polishing cut surfaces of the obtained chips in one batch; and forming patterns on the polished chips.